Donald Trump taking questions in the Roosevelt Room of the White House on Tuesday. (Rex)

Donald Trump took aim at China in his latest Twitter tirade, blaming them for the lack of progress in North Korea’s denuclearisation programme.

The US President sent a loaded message to Kim Jong Un in a series of tweets where he warned he could ‘instantly’ restart military exercises with South Korea.

Mr Trump said the exercises could be ‘far bigger than ever before’, in a string of tweets which will case doubts over his supposed warming of relations with the North Korean autocrat.

Military leaders were caught by surprise in June when Mr Trump announced the suspension with the South, ‘unless and until we see the future negotiation is not going along like it should’. He called the drills costly and provocative.

Donald Trump developed what appeared to be a warmer relationship with Kim Jong Un, pictured here in an undated handout image. (Reuters)

Mr Trump said, citing what was presented as a White House statement: ‘The president believes that his relationship with Kim Jong Un is a very good and warm one, and there is no reason at this time to be spending large amounts of money on joint US-South Korea war games.

‘Besides, the president can instantly start the joint exercises again with South Korea, and Japan, if he so chooses. If he does, they will be far bigger than ever before.’

The cancellation was an olive branch to Pyongyang, which has long complained that the exercises were invasion preparations. Often the North has reacted to the exercises with its own demonstrations of military might, including firing a new intermediate-range missile over Japan last year as a countermeasure to the drills.

…considerable aid, including money, fuel, fertilizer and various other commodities. This is not helpful! Nonetheless, the President believes that his relationship with Kim Jong Un is a very good and warm one, and there is no reason at this time to be spending large amounts…

There was some hope that the gesture of shelving the exercises would foster goodwill and help nudge the North in the denuclearisation talks.

But beyond returning the apparent remains of about 55 US troops missing since the Korean War, and its continuing suspension in its missile and nuclear tests, there has been little movement from the North.

As a result, the US last week shelved a planned trip to Pyongyang by secretary of state Mike Pompeo, citing lack of progress on denuclearisation, but remaining open to future talks.

As doubts grow in Washington and beyond over Mr Kim’s willingness to relinquish his weapons, Mr Trump has been heaping blame on China, which is North Korea’s traditional ally and main trading partner.

On Wednesday, the president accused Beijing of pressuring the North because of tensions in US-China trade relations, and also of providing North Korea with money, fuel, fertiliser and other commodities, which he said was not helpful.

China co-operated with the US last year in adopting tough international sanctions against North Korea and maintains it is still enforcing the restrictions adopted by the UN Security Council.

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But in his tweets, Mr Trump also signalled that the US has its own military means of exerting pressure on Pyongyang. His remarks compounded confusing messages from the Pentagon over the past two days that have revived speculation over the drills.

On Tuesday, defence secretary Jim Mattis told reporters the US might carry out drills with South Korea next spring after cancelling a major exercise this summer. He said no decision had been made on when to resume military exercises, but his statements suggested the recent cancellation might not be repeated.